The listing, which recognises the two sites' architectural and historic importance, followed advice from English Heritage and is part of an ongoing project to ensure the best Cold War structures are preserved.

Dr Simon Thurley, chief executive of English Heritage, said the remains of the Cold War were "fading from view faster than those of the world wars".

"These two missile sites are among the few physical reminders in this country of the Cuban missile crisis, a moment when the entire world held its breath," he said.

He added that they deserve to be protected "to remind present and future generations of this knife-edge moment in history".

Similarly, Heritage Minister Ed Vaizey said Cold War heritage was "often overlooked", adding that the sites were "an important reminder of a point in history" and therefore "worthy of protection".

"Listing these two missile sites is particularly poignant on the 50th anniversary of the Cuban missile crisis and serves as a very physical reminder of an uncertain and tense period where the world feared a nuclear war," he said.

In total, 60 Thor missiles, developed by the US, were deployed at 20 sites in the east of England from 1958 under the codename "Project Emily".

They were manned by the RAF, although their warheads remained under US control.

The decision to launch them would have been made jointly by the two countries.

RAF North Luffenham is now St George's Barracks, while RAF Harrington is now mostly farmland.